Do you compensate for the variables introduced by the recording studio itself— mics, mic placement, room acoustics, etc.—as you listen and compare?
I think if someone wants to match the sound of original recordings, it’s much easier with live recordings. The studio recordings have too many variables that we don’t truly know. I base my amps’ sounds on the essence of the original sound or of an original amp. They all varied. There is no single original sound of these amps. That’s the beauty of it. I also think one shouldn’t copy someone else but use it to learn and build off of.

Do you also do repair work or mods?
In the beginning, I did it for experience or for people who needed it, but I usually try to stay away from it. A lot of modern amps are built very differently from the older ones, and the time I spent working on amps that could just get fixed at a local music store was time I wasn’t spending on building a custom unit or getting more knowledge by tweaking a custom unit. I do repair old stuff, just not new stuff—but I don’t actively seek [old-gear repair work] out. It’s more like, if someone is stuck—like their old Marshall stopped working and they’re worried about taking it to a tech they don’t trust. People sometimes contact me from the internet and want to send in stuff for repair. I tell them to get the work done locally, if possible, because there’s that risk of the amp being damaged in shipping. I kind of treat it on a case-by-case basis.

That type of honesty is pretty rare. A lot of guys will do whatever it takes just to get work in the door.
With anything I’ve ever sold, I’ve always told them, “For the rest of your life, if you ever have any problems with anything, just let me know. If you change your playing style, I’ll re-tweak it.” I’m always worried about what the customer wants—that’s how I do everything.

Why are NOS parts are so important?
The old resistors in ’60s Marshall plexis sound much different than resistors made from the ’80s until the present. They have a smooth, warm, classic sound that I don’t hear in modern resistors—it’s easily heard in an A/B comparison for most positions in the circuit. And I’m not talking about old carbon-composition resistors—although they, too, provide a certain flavor of tone in certain spots in these amps. I just don’t prefer them all the way through, because then it loses high-end fidelity and doesn’t sound like a Marshall.

But NOS parts are only part of the puzzle. You have to know what to do with them and which ones to select, and you have to have a very finely tuned ear to do this. It’s more than just whipping together a recipe.

Is shelf life a concern with NOS parts?
I suppose any NOS part does have a shelf life if you’re talking about a long enough time frame. I won’t use old electrolytic capacitors for obvious reasons—they dry out. Also, depending on how the parts were stored—and just because they’re old parts in general, with different manufacturing processes than today—you can get ones that are way off tolerance. Sometimes that can be a good thing or a bad thing.

Do you test all of your NOS parts?
I measure each part, and I sometimes utilize components that do not measure what they actually are supposed to. I have a large stash of vintage parts. Sometimes certain part values measure near spec, and others always measure higher or lower. I’m not talking about different-toleranced parts, but ones that were supposed to have the same tolerance. By having a large selection go through my hands, I’ve been able to figure out some things that someone with a smaller quantity wouldn’t know. You can’t just look at an amp’s insides and copy it, because it will not sound the same. There’s more than meets the eye.

Featuring white rolled Tolex, sleek elegant rolled edges, gold piping and trim, and handwired series Marshall pinstripe grille cloth. Custom Shop EVH Peavey Wolfgang Moonburst guitar with detailed flame maple. Photo-by-Andy.com

Tell us about some of your builds.
My most recent amp is based on a 1966 Marshall JTM45/100. I went all out on details, so it’s cosmetically and sonically like the original. The back panel has the proper gold font—even the misaligned “III” in “MK III”—and the dot in the second “i” in “Amplifier” is slightly oval, as per the original amps. The gold knobs on the front panel are old and nearly identical to vintage Marshalls. The circuit board is NOS Paxolin, as per the originals. This does have an effect on the sound. I used all NOS original resistors found in amps from that era. The coupling capacitors are original Mullards with a date code of 1966.

I sourced as many original components as possible from all over the world. I even managed to source original PVC [polyvinyl-chloride-plastic-insulated] stranded wire from a guy in England who supplied Marshall with them in the ’60s. I also sourced the original pink wire to the pots and the slightly thicker diameter pink wire for the pot jumpers and input jacks, as per original amps of this era—this wire is next to extinct and plays a role in the vintage tone.

How so?
The old wire had a different molecular structure, a different strand arrangement, and a different grade of PVC. Also, the old Marshall carbon-film resistors I used are part of the tone of this era. I find modern carbon-film resistors much too bright for these amps, and carbon-composition resistors lack too much high-end fidelity.

I have experimented and A/B’d different wire. I can tell the difference between stranded and solid-core wire. I can also tell the difference between cloth-covered and stranded PVC wire. To take it a step further, there is a difference if the stranded wire is twisted inside the PVC, or if it’s all laid out parallel to each other. I see many builders today using bonded or top-coated stranded wire, and I don’t like this wire for vintage Marshall amps. It doesn’t sound right.

What specifically doesn’t sound right about it?
Notice I said it doesn’t sound “right,” but I didn’t say “bad.” We are talking about vintage Marshall tube amplifiers and recreating that original tone. The top-coated or bonded wire does not transfer the signal the same as a stranded wire does. By stranded, I mean the wire’s strands are easily separated and not tinned into one conductor. There’s more detail in the high-end with stranded wire. It’s harder to work with, but I much prefer the tone for these amps. After all, isn’t that the whole point of the build—the tone?

I think a lot of guys use top-coated wire because they don’t believe it can have an effect on the tone, or it’s easier to work with, or they simply don’t pay attention to the details like I do—or their ears can’t hear the difference. I am really particular about the kind of wire I use in different circuits, and where I use it in the circuits.

How do you find your parts?
The best way to find the original parts is to spend an enormous amount of time contacting every ham radio guy from England there is. It’s similar to how guys find parts for old classic cars. You really have to spend a lot of time digging. I love this part of rebuilding some of the old amps, though! There are guys I regularly stay in contact with from England, and I love that they know I am putting parts they saved for the past 40 or 45 years to good use. I read an interview with Jeff Beck not too long ago and he talked about looking for car parts in America to complete his hot rods. Same deal there.

Are there enough parts to go around to make a big run of vintage replicas?
I have a large amount of vintage parts for multiple vintage amp builds, but I treat it on a case-by-case basis. If I were building a high quantity of my own designs, I would source new parts that gave me the tone I wanted.

What do you do if you can’t locate an NOS part?
If I can’t find an original part, I often make my own replacement part. In the JTM45/100 replica, I made my own internal fuse holder. I design and make my own circuit boards for my amps and pedals. I make my own wah inductors, too. For wah pots, one way I build them is by swapping the internal phenolic wafer from an old pot into a new wah pot casing. In guitars, I modify the pot’s internal carbon track for a higher resistance, so they sound more like the pots found in old Les Pauls. If making my own part is not an option, I’ll source an alternative NOS part or, if needed, a new part that reacts and sounds as close as possible to the original.

Would you later replace that part with an NOS part if you were able to track one down?
Yes, but mostly on strict vintage builds.